dried fruit is not a great idea. too much sugar. dried rosehips are good but i'm not sure if there are rose species that are suitable and some that are not.
generally, the plainer diet the better. hay, pellets, water and an occasional healthy treat. this could be rolled oats, a rosehip, alfalfa hay, some people give shredded wheat. a treat once or twice a week is enough. sugary things like raisins are very popular with the chins but shouldn't be given often.
if you have untreated apple/pear trees, you could chop up some little branches but you'll have to boil them and bake them first.
you need to be very careful about giving gizmo new things - the bacteria in their tummy takes about a month to change according to the food they're eating so any change has to be extremely gradual. if there's a sudden change, too many treats or too much sugar, there is a risk of them going into gi stasis - this is a very painful and dangerous condition, my rescue girl has had it a few times (she has tummy problems since she was fed on completely wrong stuff and she has to be on antibiotics every so often because of other health problems so they don't help with the gut either) and the first time she very nearly died. treatment doesn't always work. she had 15 injections in a week and all the vets thought she wasn't going to make it.
the problem with sugary treats is also that they fulfil the calorie intake requirement a lot quicker than hay without much chewing action - this means that the teeth are not being worn down as they should and long term this causes dental problems.
my mae was fed on banana chips and chinchilla mix without any hay. when i got her, she had about a week to live, she was severely undernourished (to the point where they could not even do an xray for her teeth because she would not have survived the anaesthetic), had spikes and spurs on her teeth that were cutting her cheeks, had one fractured tooth that had to be pulled out, she has a chronic jaw bone infection which is causing the bone to extend downwards so she pretty much has a tusk. these all could have been prevented if she was fed the right diet.
her tummy is so messed up now that the only treat i'm not afraid to give her is rolled oats and alfalfa hay. anything else makes her sick.
the best way of monitoring how things are going is keeping an eye on the poo
